1. Field of the Invention
The present invention relates generally to a paging system and its operating method, and more particularly to a paging system with a message display unit.
2. Description of the Related Art
There has recently been a marked development in the field of mobile radio communications service, and paging systems is one of the representative areas of this field. Paging systems provide the simple service of transmitting messages only one way, and the number of subscribers per radio wave is by far greater than for other systems (e.g., automobile telephone systems). As a result, their subscription fees are low and their use has spread rapidly. However, pager systems have recently been improved so as to operate not only the calling service but also to display messages on the pager.
A paging system with a message display service comprises at least a paging control unit connected to a public telephone network, a transmitter connected to the paging control unit and a plurality of pagers for receiving the paging signal transmitted from the transmitter. When a paging request call originates through a public telephone network, the paging control unit accepts the incoming call along with the subscriber's number and message data, converts the incoming call into a paging signal including the address code of the pager and a message signal referring to a subscriber file, which retains the corresponding relation between the subscriber's number and an address code for the pager, and transfers the converted paging signal to the transmitter. The transmitter transmits the paging signal in the form of radio waves. On the other hand, each pager is provided with a receiving circuit tuned for its specific address code selectively, a control unit to store a succeeding message signal in a storage unit, and a display means to display the message on a display unit (prior art document, Japanese Patent No. 64097/1988, discloses the constitution of a pager with a display function).
Although such a paging system is quite effective, it is still somewhat inconvenient because it only affords one-way service. Pager carriers often worry that some messages might not be received. Paging systems used with message-displaying pagers have the advantage that a plurality of callers may send messages incorporating the callers, names so as to distinguish who sent the messages, but the receiving parties tend to worry about the possibility that some messages may remain unreceived without any way to check for them.